Physical and anatomical features of Acacia mangium planted in Sarawak, Malaysia

The Acacia mangium is a major species planted in the reforestration sites throughout the State of Sarawak. To complement reforestration project, the economic utilisation of this species must be found in order to be sustainable. The utilisation potential depends on the properties of the timber. This study investigated and quantified the physical and anatomical features of 13-year old Acacia mangium planted in Compartment No. 8401 and 8402 in Sampadi Forest Reserve, Lundu, Kuching, Sarawak. In this study, 12 timber sample discs were collected at DBH and specimens were made from two strips crossing one another through the pith at 90 degrees. The physical features that are important to the utilisation aspect of the timber are the thickness of sapwood, colour and density. The anatomical features that have the greatest influence on wood properties and secondary processing are the vessels parameters (such as vessel grouping and arrangement, diameter, content, frequency and vessel element length), and fibre parameters (such as length, diameter and fibre wall thickness). The average thickness of the sapwood is 11 mm, whitish in colour and the heartwood is slightly pale brownish to purplish brown on prolonged exposure. Average oven-dried density of 469 kg/m3, substantial variation amongst tree from 419 to 584 kg/m3, higher variation within a tree of 340 kg/m3 at the pith and 585 kg/m3 at the sapwood, and density increases towards the sapwood. Mostly solitary vessels, multiple vessels common especially multiple of 2, average diameter of 200 mu m*, progressively increases towards the sapwood, 4 vessels/mm2*, evenly distributed. Average vessel element length of 332 mu m that also increases towards the sapwood. The average fibre length is 1,073 m that also increases towards the sapwood. Fibre length variation is higher from the pith up to 80 mm radially and variation decreases to constant length towards the sapwood. Preliminary findings showed that fibre diameter and fibre wall thickness do not showed significant increases from the pith to sapwood. Preliminary results as some measurements and counting are still not completed and this data will be amended in the paper later.